WASHINGTO (Reuters) -- The UAW filed an appeal today with the U.S. government, asking it to set aside the results of an election last week where workers at a Tennessee Volkswagen plant voted not to join the union.

Citing what it called "interference by politicians and outside special interest groups," the union said the U.S. National Labor Relations Board would investigate the election and decide if there are grounds to scrap it and hold a new one.

Labor lawyers and academics said last week it would be difficult for the union to make a case for setting aside the election. They said labor law does not limit what can be said in a union election campaign by politicians, as long as they are stating their own views and not doing the bidding of management.

The law does strictly limit the statements that can be made by management and the union itself, they said.

The UAW said in a statement that its appeal details "a coordinated and widely publicized coercive campaign conducted by politicians and outside organizations to deprive Volkswagen workers of their federally protected right to join a union."

The election result at the plant in Chattanooga was a blow to the UAW, which has been unable to organize workers at foreign-owned auto plants in the American South.

Conservative Republicans spoke out against the UAW in the final days of the election campaign. Among the most vocal critics of the union was U.S. Bob Corker, R-Tenn., the former mayor of Chattanooga.

The UAW said its appeal calls Corker's conduct "shameful and undertaken with utter disregard for the rights of the citizens of Tennessee and surrounding states that work at Volkswagen."

President Barack Obama last week accused politicians in Chattanooga of being "more concerned about German shareholders than American workers," according to a Democratic aide who heard the remarks at a closed meeting with lawmakers.